Orthopaedic surgery is often carried out on operating tables comprising traction systems, principally used for operations on the lower limbs of a patient, which are composed of traction arms comprising mechanical screw tractors. These traction arms are fixed on a frame which comprises the elements necessary for supporting the patient's pelvis. These traction arms may be articulated horizontally and vertically.
At the present time, orthopaedic surgery makes use of per-operatory radiological control in intensive manner. The control apparatus with radiogenic source, and particularly the luminance amplifiers, require easy access to the operative field.
The systems of articulation of the orthopaedic traction devices, which are generally voluminous and lie in the axis of the operative field, prevent maximum use of the apparatus with radiogenic source. Furthermore, the traction devices designed for maximum use of the apparatus with radiogenic source are not easy to handle and their traction arms are only partially articulated.
For example, British Patent No. 2 111 834 discloses a device comprising a frame; two lateral arms articulated on the frame so as to be horizontally mobile, the arms being provided with means for locking in position and traction means; and a pelvis support connected to the frame and adjustable laterally with respect to the median plane of the frame. In this device, the articulation of the arms allows only their horizontal displacement, which is insufficient to respond to all requirements in orthopaedic surgery. Moreover, the means for locking the arms, made in the form of clamping levers disposed at the level of the articulated joints, are of difficult access when the operative field is already encumbered with ancillary apparatus.